3.4 - Motherboard Connectors

Question 1

24-pin motherboard power

Answer 1

• Main motherboard power
  – Provides +3.3 V, +/-5 V, and +/- 12 V
• 20 pin connector was the original ATX standard
  – 24 pin was added for PCI Express power
• You can connect a 24-pin connector to a 20-pin
  motherboard
  – Some cables are 20-pin + 4-pin

Question 2

4-pin ATX

Answer 2

• 4-pin ATX +12 V power
  – ATX12V Advanced Technology Extended motherboards
• Additional 12 volt power for older motherboards
  – Used primarily for CPU
• May be labeled ATX12V, P4, or CPU
  – And keyed for the appropriate connector

Question 3

Headers

Answer 3

• A pin header
  – A simple electrical interface
  – The connector is attached to the header
• Many different uses
  – Power, peripheral connections, lights, and buttons